external/bsd/bind/dist/lib/isc/base32.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (C) 2008, 2009  Internet Systems Consortium, Inc. ("ISC")
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  11  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  12  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  13  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  14  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  15  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  16  * PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 /* Id: base32.c,v 1.6 2009/10/21 01:22:29 each Exp */
  20
  21 /*! \file */
  22
  23 #include <config.h>
  24
  25 #include <isc/base32.h>
  26 #include <isc/buffer.h>
  27 #include <isc/lex.h>
  28 #include <isc/region.h>
  29 #include <isc/string.h>
  30 #include <isc/util.h>
  31
  32 #define RETERR(x) do { \
  33         isc_result_t _r = (x); \
  34         if (_r != ISC_R_SUCCESS) \
  35                 return (_r); \
  36         } while (0)
  37
  38
  39 /*@{*/
  40 /*!
  41  * These static functions are also present in lib/dns/rdata.c.  I'm not
  42  * sure where they should go. -- bwelling
  43  */
  44 static isc_result_t
  45 str_totext(const char *source, isc_buffer_t *target);
  46
  47 static isc_result_t
  48 mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length);
  49
  50 /*@}*/
  51
  52 static const char base32[] =
  53          "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567=abcdefghijklmnopqrstuvwxyz234567";
  54 static const char base32hex[] =
  55         "0123456789ABCDEFGHIJKLMNOPQRSTUV=0123456789abcdefghijklmnopqrstuv";
  56
  57 static isc_result_t
  58 base32_totext(isc_region_t *source, int wordlength, const char *wordbreak,
  59               isc_buffer_t *target, const char base[])
  60 {
  61         char buf[9];
  62         unsigned int loops = 0;
  63
  64         if (wordlength >= 0 && wordlength < 8)
  65                 wordlength = 8;
  66
  67         memset(buf, 0, sizeof(buf));
  68         while (source->length > 0) {
  69                 buf[0] = base[((source->base[0]>>3)&0x1f)];     /* 5 + */
  70                 if (source->length == 1) {
  71                         buf[1] = base[(source->base[0]<<2)&0x1c];
  72                         buf[2] = buf[3] = buf[4] = '=';
  73                         buf[5] = buf[6] = buf[7] = '=';
  74                         RETERR(str_totext(buf, target));
  75                         break;
  76                 }
  77                 buf[1] = base[((source->base[0]<<2)&0x1c)|      /* 3 = 8 */
  78                               ((source->base[1]>>6)&0x03)];     /* 2 + */
  79                 buf[2] = base[((source->base[1]>>1)&0x1f)];     /* 5 + */
  80                 if (source->length == 2) {
  81                         buf[3] = base[(source->base[1]<<4)&0x10];
  82                         buf[4] = buf[5] = buf[6] = buf[7] = '=';
  83                         RETERR(str_totext(buf, target));
  84                         break;
  85                 }
  86                 buf[3] = base[((source->base[1]<<4)&0x10)|      /* 1 = 8 */
  87                               ((source->base[2]>>4)&0x0f)];     /* 4 + */
  88                 if (source->length == 3) {
  89                         buf[4] = base[(source->base[2]<<1)&0x1e];
  90                         buf[5] = buf[6] = buf[7] = '=';
  91                         RETERR(str_totext(buf, target));
  92                         break;
  93                 }
  94                 buf[4] = base[((source->base[2]<<1)&0x1e)|      /* 4 = 8 */
  95                               ((source->base[3]>>7)&0x01)];     /* 1 + */
  96                 buf[5] = base[((source->base[3]>>2)&0x1f)];     /* 5 + */
  97                 if (source->length == 4) {
  98                         buf[6] = base[(source->base[3]<<3)&0x18];
  99                         buf[7] = '=';
 100                         RETERR(str_totext(buf, target));
 101                         break;
 102                 }
 103                 buf[6] = base[((source->base[3]<<3)&0x18)|      /* 2 = 8 */
 104                               ((source->base[4]>>5)&0x07)];     /* 3 + */
 105                 buf[7] = base[source->base[4]&0x1f];            /* 5 = 8 */
 106                 RETERR(str_totext(buf, target));
 107                 isc_region_consume(source, 5);
 108
 109                 loops++;
 110                 if (source->length != 0 && wordlength >= 0 &&
 111                     (int)((loops + 1) * 8) >= wordlength)
 112                 {
 113                         loops = 0;
 114                         RETERR(str_totext(wordbreak, target));
 115                 }
 116         }
 117         if (source->length > 0)
 118                 isc_region_consume(source, source->length);
 119         return (ISC_R_SUCCESS);
 120 }
 121
 122 isc_result_t
 123 isc_base32_totext(isc_region_t *source, int wordlength,
 124                   const char *wordbreak, isc_buffer_t *target)
 125 {
 126         return (base32_totext(source, wordlength, wordbreak, target, base32));
 127 }
 128
 129 isc_result_t
 130 isc_base32hex_totext(isc_region_t *source, int wordlength,
 131                      const char *wordbreak, isc_buffer_t *target)
 132 {
 133         return (base32_totext(source, wordlength, wordbreak, target,
 134                               base32hex));
 135 }
 136
 137 /*%
 138  * State of a base32 decoding process in progress.
 139  */
 140 typedef struct {
 141         int length;             /*%< Desired length of binary data or -1 */
 142         isc_buffer_t *target;   /*%< Buffer for resulting binary data */
 143         int digits;             /*%< Number of buffered base32 digits */
 144         isc_boolean_t seen_end; /*%< True if "=" end marker seen */
 145         int val[8];
 146         const char *base;       /*%< Which encoding we are using */
 147         int seen_32;            /*%< Number of significant bytes if non zero */
 148 } base32_decode_ctx_t;
 149
 150 static inline void
 151 base32_decode_init(base32_decode_ctx_t *ctx, int length,
 152                    const char base[], isc_buffer_t *target)
 153 {
 154         ctx->digits = 0;
 155         ctx->seen_end = ISC_FALSE;
 156         ctx->seen_32 = 0;
 157         ctx->length = length;
 158         ctx->target = target;
 159         ctx->base = base;
 160 }
 161
 162 static inline isc_result_t
 163 base32_decode_char(base32_decode_ctx_t *ctx, int c) {
 164         char *s;
 165         unsigned int last;
 166
 167         if (ctx->seen_end)
 168                 return (ISC_R_BADBASE32);
 169         if ((s = strchr(ctx->base, c)) == NULL)
 170                 return (ISC_R_BADBASE32);
 171         last = s - ctx->base;
 172         /*
 173          * Handle lower case.
 174          */
 175         if (last > 32)
 176                 last -= 33;
 177         /*
 178          * Check that padding is contiguous.
 179          */
 180         if (last != 32 && ctx->seen_32 != 0)
 181                 return (ISC_R_BADBASE32);
 182         /*
 183          * Check that padding starts at the right place and that
 184          * bits that should be zero are.
 185          * Record how many significant bytes in answer (seen_32).
 186          */
 187         if (last == 32 && ctx->seen_32 == 0)
 188                 switch (ctx->digits) {
 189                 case 0:
 190                 case 1:
 191                         return (ISC_R_BADBASE32);
 192                 case 2:
 193                         if ((ctx->val[1]&0x03) != 0)
 194                                 return (ISC_R_BADBASE32);
 195                         ctx->seen_32 = 1;
 196                         break;
 197                 case 3:
 198                         return (ISC_R_BADBASE32);
 199                 case 4:
 200                         if ((ctx->val[3]&0x0f) != 0)
 201                                 return (ISC_R_BADBASE32);
 202                         ctx->seen_32 = 3;
 203                         break;
 204                 case 5:
 205                         if ((ctx->val[4]&0x01) != 0)
 206                                 return (ISC_R_BADBASE32);
 207                         ctx->seen_32 = 3;
 208                         break;
 209                 case 6:
 210                         return (ISC_R_BADBASE32);
 211                 case 7:
 212                         if ((ctx->val[6]&0x07) != 0)
 213                                 return (ISC_R_BADBASE32);
 214                         ctx->seen_32 = 4;
 215                         break;
 216                 }
 217         /*
 218          * Zero fill pad values.
 219          */
 220         ctx->val[ctx->digits++] = (last == 32) ? 0 : last;
 221
 222         if (ctx->digits == 8) {
 223                 int n = 5;
 224                 unsigned char buf[5];
 225
 226                 if (ctx->seen_32 != 0) {
 227                         ctx->seen_end = ISC_TRUE;
 228                         n = ctx->seen_32;
 229                 }
 230                 buf[0] = (ctx->val[0]<<3)|(ctx->val[1]>>2);
 231                 buf[1] = (ctx->val[1]<<6)|(ctx->val[2]<<1)|(ctx->val[3]>>4);
 232                 buf[2] = (ctx->val[3]<<4)|(ctx->val[4]>>1);
 233                 buf[3] = (ctx->val[4]<<7)|(ctx->val[5]<<2)|(ctx->val[6]>>3);
 234                 buf[4] = (ctx->val[6]<<5)|(ctx->val[7]);
 235                 RETERR(mem_tobuffer(ctx->target, buf, n));
 236                 if (ctx->length >= 0) {
 237                         if (n > ctx->length)
 238                                 return (ISC_R_BADBASE32);
 239                         else
 240                                 ctx->length -= n;
 241                 }
 242                 ctx->digits = 0;
 243         }
 244         return (ISC_R_SUCCESS);
 245 }
 246
 247 static inline isc_result_t
 248 base32_decode_finish(base32_decode_ctx_t *ctx) {
 249         if (ctx->length > 0)
 250                 return (ISC_R_UNEXPECTEDEND);
 251         if (ctx->digits != 0)
 252                 return (ISC_R_BADBASE32);
 253         return (ISC_R_SUCCESS);
 254 }
 255
 256 static isc_result_t
 257 base32_tobuffer(isc_lex_t *lexer, const char base[], isc_buffer_t *target,
 258                 int length)
 259 {
 260         base32_decode_ctx_t ctx;
 261         isc_textregion_t *tr;
 262         isc_token_t token;
 263         isc_boolean_t eol;
 264
 265         base32_decode_init(&ctx, length, base, target);
 266
 267         while (!ctx.seen_end && (ctx.length != 0)) {
 268                 unsigned int i;
 269
 270                 if (length > 0)
 271                         eol = ISC_FALSE;
 272                 else
 273                         eol = ISC_TRUE;
 274                 RETERR(isc_lex_getmastertoken(lexer, &token,
 275                                               isc_tokentype_string, eol));
 276                 if (token.type != isc_tokentype_string)
 277                         break;
 278                 tr = &token.value.as_textregion;
 279                 for (i = 0; i < tr->length; i++)
 280                         RETERR(base32_decode_char(&ctx, tr->base[i]));
 281         }
 282         if (ctx.length < 0 && !ctx.seen_end)
 283                 isc_lex_ungettoken(lexer, &token);
 284         RETERR(base32_decode_finish(&ctx));
 285         return (ISC_R_SUCCESS);
 286 }
 287
 288 isc_result_t
 289 isc_base32_tobuffer(isc_lex_t *lexer, isc_buffer_t *target, int length) {
 290         return (base32_tobuffer(lexer, base32, target, length));
 291 }
 292
 293 isc_result_t
 294 isc_base32hex_tobuffer(isc_lex_t *lexer, isc_buffer_t *target, int length) {
 295         return (base32_tobuffer(lexer, base32hex, target, length));
 296 }
 297
 298 static isc_result_t
 299 base32_decodestring(const char *cstr, const char base[], isc_buffer_t *target) {
 300         base32_decode_ctx_t ctx;
 301
 302         base32_decode_init(&ctx, -1, base, target);
 303         for (;;) {
 304                 int c = *cstr++;
 305                 if (c == '\0')
 306                         break;
 307                 if (c == ' ' || c == '\t' || c == '\n' || c== '\r')
 308                         continue;
 309                 RETERR(base32_decode_char(&ctx, c));
 310         }
 311         RETERR(base32_decode_finish(&ctx));
 312         return (ISC_R_SUCCESS);
 313 }
 314
 315 isc_result_t
 316 isc_base32_decodestring(const char *cstr, isc_buffer_t *target) {
 317         return (base32_decodestring(cstr, base32, target));
 318 }
 319
 320 isc_result_t
 321 isc_base32hex_decodestring(const char *cstr, isc_buffer_t *target) {
 322         return (base32_decodestring(cstr, base32hex, target));
 323 }
 324
 325 static isc_result_t
 326 base32_decoderegion(isc_region_t *source, const char base[], isc_buffer_t *target) {
 327         base32_decode_ctx_t ctx;
 328
 329         base32_decode_init(&ctx, -1, base, target);
 330         while (source->length != 0) {
 331                 int c = *source->base;
 332                 RETERR(base32_decode_char(&ctx, c));
 333                 isc_region_consume(source, 1);
 334         }
 335         RETERR(base32_decode_finish(&ctx));
 336         return (ISC_R_SUCCESS);
 337 }
 338
 339 isc_result_t
 340 isc_base32_decoderegion(isc_region_t *source, isc_buffer_t *target) {
 341         return (base32_decoderegion(source, base32, target));
 342 }
 343
 344 isc_result_t
 345 isc_base32hex_decoderegion(isc_region_t *source, isc_buffer_t *target) {
 346         return (base32_decoderegion(source, base32hex, target));
 347 }
 348
 349 static isc_result_t
 350 str_totext(const char *source, isc_buffer_t *target) {
 351         unsigned int l;
 352         isc_region_t region;
 353
 354         isc_buffer_availableregion(target, &region);
 355         l = strlen(source);
 356
 357         if (l > region.length)
 358                 return (ISC_R_NOSPACE);
 359
 360         memcpy(region.base, source, l);
 361         isc_buffer_add(target, l);
 362         return (ISC_R_SUCCESS);
 363 }
 364
 365 static isc_result_t
 366 mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length) {
 367         isc_region_t tr;
 368
 369         isc_buffer_availableregion(target, &tr);
 370         if (length > tr.length)
 371                 return (ISC_R_NOSPACE);
 372         memcpy(tr.base, base, length);
 373         isc_buffer_add(target, length);
 374         return (ISC_R_SUCCESS);
 375 }